Obesity Hypoventilation Syndrome: Choosing the Appropriate Treatment of a Heterogeneous Disorder

Results of CPAP Titration and Short-Term Adherence Rates in Patients with Obesity Hypoventilation Syndrome and Mild/Moderate Obstructive Sleep Apnea

PURPOSE

No study has assessed the titration success of CPAP therapy in patients with obesity hypoventilation syndrome (OHS) and an apnea-hypopnea index (AHI) <30 event/h. This study aimed to assess the titration success of CPAP therapy under polysomnography and subsequent short-term adherence (1 month) in patients with OHS and an AHI <30 event/h.

METHODS

Consecutive OHS patients with an AHI <30 events/h between 2010 and 2019 were included (n=54). All OHS patients were first started on CPAP during the therapeutic sleep-study. If the therapeutic-study showed that the SpO2 remained < 90% for 20% of the total sleep time, a second therapeutic study was arranged with bi-level PAP (BPAP). Thirty patients agreed to participate in the 1-month follow-up adherence study. We applied the American-Thoracic-Society criteria for PAP adherence.

RESULTS

The mean age was 54.8±14.6 years, and the mean BMI was 45.9±12.2 kg/m². Successful titration on CPAP was attained in 36 (66.7%) patients, and 18 (33.3%) required BPAP. Patients who failed the CPAP trial had a significantly higher PaCO2 and bicarbonate, a more restrictive respiratory pattern on spirometry, and a significantly higher time with SpO2<90% (mins) during sleep. The only independent correlate of CPAP-titration success on the multivariable regression analysis was the desaturation index (OR: 1.33 [1.033-1.712]). More than 80% of the participants were using CPAP therapy after one-month with no differences in adherence between the CPAP and BPAP groups.

CONCLUSIONS

The current results suggest that CPAP therapy could be an acceptable alternative therapy to BPAP in patients with OHS without severe OSA.

Long-Term Adherence to Positive Airway Pressure Therapy in Saudi Ambulatory Patients with Obesity Hypoventilation Syndrome and Severe Obstructive Sleep Apnea: A One-Year Follow-Up Prospective Observational Study

PURPOSE

Long-term studies assessing positive airway pressure (PAP) therapy adherence in patients with obesity hypoventilation (OHS) are limited. The aim of this study was to assess PAP therapy adherence in Arab (Saudi) patients with OHS and an apnea-hypopnea index (AHI) >30/h.

METHODS

A prospective cohort study of consecutive adult patients diagnosed with OHS between March 2010 and September 2019 was conducted. During the therapeutic sleep study, all OHS patients were started on continuous PAP (CPAP). Patients who failed to maintain oxygen saturation ≥88% despite the elimination of obstructive respiratory events were shifted to bi-level PAP (BPAP). Objective assessment of adherence was performed at 1, 6, and 12 months after initiating PAP therapy. We adopted the American-Thoracic-Society criteria for PAP adherence.

RESULTS

The study included 101 patients (women = 65 patients) with OHS, an AHI ≥30/h, and a mean age of 54.9 ± 12.7 years. Successful titration on CPAP was achieved in 64.4% of the patients and BPAP was required for 35.6% of the patients who failed CPAP titration. At the end of the study, 43.6% of the patients used PAP therapy in an acceptable manner. Adherence after 1 and 6 months was the only independent predictors of adherence at 12 months.

CONCLUSION

PAP adherence among Saudi patients with OHS and severe obstructive sleep apnea was relatively low. Almost two-thirds of patients tolerated CPAP titration with the elimination of respiratory events and desaturation. Early adherence to PAP therapy was the only predictor of PAP therapy adherence at the end of the study.

Obesity Hypoventilation: Traditional Versus Nontraditional Populations

Obesity hypoventilation syndrome is the most frequent cause of chronic hypoventilation and is increasingly more common with rising obesity rates. It leads to considerable morbidity and mortality, particularly when not recognized and treated adequately. Long-term nocturnal noninvasive ventilation is the mainstay of treatment but evidence suggests that CPAP may be effective in stable patients. Specific perioperative management is required to reduce complications. Some unique syndromes associated with obesity and hypoventilation include rapid-onset obesity with hypoventilation, hypothalamic, autonomic dysregulation (ROHHAD), and Prader-Willi syndrome. Congenital central hypoventilation syndrome (early or late-onset) is a genetic disorder resulting in hypoventilation. Several acquired causes of chronic central hypoventilation also exist. A high level of clinical suspicion is required to appropriately diagnose and manage affected patients.

Comparison between auto-trilevel and bilevel positive airway pressure ventilation for treatment of patients with concurrent obesity hypoventilation syndrome and obstructive sleep apnea syndrome

PURPOSE

Our study aims to compare the difference in clinical efficacy between auto-trilevel positive airway pressure (auto-trilevel PAP) ventilator and conventional fixed bilevel positive airway pressure (BiPAP) ventilator for obesity hypoventilation syndrome (OHS) patients with coexisting moderate or severe obstructive sleep apnea hypopnea syndrome (OSAHS).

METHODS

Twenty-three OHS patients with moderate or severe OSAHS enrolled between January 2015 and September 2017 underwent ventilation by three different modes of positive airway pressure (PAP) for 8 h per night. A single variable mode was applied at the first night followed by two nights when no PAP therapy was carried out as a washout period between each mode. The inspiratory positive airway pressure (IPAP) decided by PaCO₂ was consistently used for modes 1, 2, and 3. In mode 1, the expiratory positive airway pressure (EPAP) issued by BiPAP was decided by the minimal PAP levels for cessation of snoring. However, in mode 2, the EPAP was fixed at 3 cmH₂O higher than this value. With the use of auto-trilevel PAP in mode 3, the EPAP was set to initially match that of mode 1 but the end of EPAP (EEPAP) was automatically regulated to be elevated according to upper airway patency condition. We also compared the following parameters including apnea hypopnea index (AHI), minimal SpO₂ (miniSpO₂), arousal index, and sleep efficiency during sleep; PaCO₂ in the morning and Epword sleepiness score (ESS) at daytime were measured prior to and during PAP treatment as well as between three selected PAP modes.

RESULTS

Compared with the parameters before ventilation therapies, all three variable modes of ventilation were associated with a higher nocturnal miniSpO₂ and sleep efficiency (all P < 0.01). Among the three variable modes, mode 3 resulted in not only the lowest arousal index and daytime ESS but also the highest sleep efficiency. Compared to mode 1, mode 2 demonstrated a significantly reduced AHI and an elevated miniSpO₂ and morning PaCO₂ (all P < 0.05), while mode 3 was associated with a decreased AHI, an increased miniSpO₂ (all P < 0.05), and no statistical change of PaCO₂ following the end of PAP treatment (P > 0.05). Comparison between mode 2 and mode 3 revealed that mode 3 had a significantly lower PaCO₂ (P < 0.05), but displayed no remarkable changes of AHI and miniSpO₂ (all P > 0.05).

CONCLUSION

Compared to fixed BiPAP ventilation, auto-trilevel PAP ventilation could more effectively correct hypercapnia, achieve lower index of nocturnal apnea and hypopnea, more improved sleep quality, and lower daytime sleepiness score. Auto-trilevel PAP ventilation is therefore more efficacious than conventional BiPAP ventilation in non-invasive ventilation therapy for OHS patients with concurrent moderate or severe OSAHS.

Efficacy of bilevel ventilatory support in the treatment of stable patients with obesity hypoventilation syndrome: systematic review and meta-analysis

OBJECTIVE

To systematically review the effects of bilevel ventilatory support (BVS) in patients with Obesity Hypoventilation Syndrome (OHS).

METHODS

A search of databases (MEDLINE accessed by PubMed, Cochrane CENTRAL, EMBASE and LILACS) was conducted from inception to June 2018. Randomized trials comparing BVS to other therapeutic modalities such as lifestyle counseling, continuous positive airway pressure (PAP) or BVS with average volume assured pressure support for the treatment of patients with OHS were included. The primary outcome was a change in daytime arterial carbon dioxide levels (PaCO₂). Secondary outcome measures included arterial partial pressure of oxygen (PaO₂), blood bicarbonate (HCO₃), percentage of total sleep time (TST) with oxygen saturation <90%, transcutaneous pressure of carbon dioxide (PtcCO₂), Epworth Sleepiness Scale (ESS), Medical Outcome Survey Short Form (SF36), Functional Outcomes of Sleep Questionnaire (FOSQ), Severe Respiratory Insufficiency Questionnaire (SRI), compliance with treatment, and weight loss.

RESULTS

Of 176 articles identified, seven studies were included. When BVS was compared to lifestyle counseling, the intervention was superior in improving PaCO₂ (-2.90 mmHg; 95%CI -4.28 to -1.52), PaO₂ (2.89 mmHg; 95%CI 0.33 to 5.46), HCO₃ (-2.55 mmol/L; 95%CI -3.28 to -1.81), percentage of TST<90% (-30.55%; 95%CI -37.98 to -23.12), ESS (-2.52; 95%CI -4.16 to -0.88) and FOSQ (6.33; 95%CI 1.78 to 10.88). However, when BVS was compared to other PAP modalities, there was no difference in any of the outcomes evaluated.

CONCLUSIONS

Treatment using BVS therapy is superior to lifestyle counseling. Different PAP modalities appear to be equally effective in improving outcomes. CRD42017065326.